1. Field of the Invention
This invention relates to a piezoelectric oscillator, and more particularly to a surface-mounted type piezoelectric oscillator.
2. Discussion of the Related Art
A piezoelectric oscillator, such as a quartz oscillator, has been used as a clock source for a micro computer, communications equipment, and so on, and especially in recent years, a surface-mounted type piezoelectric oscillator has been employed, in view of a easy mounting on a printed-wiring substrate. For example, JP Laid Open H4-367111 discloses a surface-mounted type piezoelectric oscillator, where a piezoelectric vibrating reed is supported by a pair of carriers which are brazed onto metal interconnects provided on a substrate. Such an oscillator comprises many parts and is unsuitable for miniaturization. Further, vibration of the oscillator is limited by the twin-carrier structure, which adversely affects the properties of the oscillator in proportion to the miniaturization.
On the other hand, JP Laid Open H4-298109 discloses a cantilevered oscillator, where a quartz oscillating reed is fixed by conductive adhesive on an attaching member having an electrode thereon for electrical connection, thereby ensuring conductivity with the oscillating reed. Such a cantilevered oscillator is superior to a twin-supported oscillator in both properties and structural simplicity, and can be made smaller and thinner.
However, in such a surface-mounted type piezoelectric oscillator having a cantilevered oscillating reed structure, a lead electrode of the oscillating reed generally extends toward only one end of the reed. For this reason, the end portion of the oscillating reed where the lead electrode exists must be precisely overlaid on the connecting electrode provided on the substrate to ensure the electrical conductivity. When the oscillating reed is placed in the reversed direction, the lead electrode does not meet the connecting electrode on the substrate, and conductivity is not obtained. Therefore, during the mounting of the oscillating reed, the direction of the oscillating reed must be confirmed so as to ensure the conductivity. When the oscillating reed is mounted in the reversed direction by mistake, it must be remounted. Thus, the mounting process of the oscillating reed is troublesome, and automation or mechanization is difficult.